Referencing of UAV point cloud with TLS point cloud for excavation surveying in Mae Moh Open-pit Coal Mine

Abstract

Electricity Generating Authority of Thailand (EGAT) Mae Moh mine uses the terrestrial laser scanner (TLS) for excavation volume determination. About 2 million sqm of complex and large terrain are scanned each month. The TLS needs a lot of scanning position for quality data and takes so much operation times, which enforces the excavation to stop for longer time and lower the production rate. Enrichment the data with the unmanned aerial vehicle (UAV) is an interesting solution, but the accuracy of the UAV is terrible, which can be resolved with fair amount of ground control point (GCP) covering the target area. However, the GCP preparing in Mae Moh mine is a time-consuming work, that cause the surveying process to be more complicate and doesn’t significantly reduce the working time. Because of these, using UAV with GCP is impractical for us. Hence, we tried to reference UAV point cloud with TLS point cloud as control point. The results revealed the height difference between UAV and TLS surface, which provide the average difference of 0.023 m. and the standard deviation of 0.013m. This amount of difference is in acceptable range, in this way, the determination of excavation volume can be rapidly done and can achieve the best result.